The invention relates to tire tread forming, and more particularly to an apparatus for molding a seamless toroidal tire tread for use in retreading of tire carcasses.
Tire retreading was at one time accomplished primarily by molding and curing of uncured rubber tread stock in situ on a tire carcass. Apparatus for this type of operation is shown in U.S. Pat. No. 3,042,966. More recently, treads for retreading tires were molded and cured separately into a linear tread strip, then assembled onto the tire carcass. This retreading practice, however, necessarily involved a seam where the two ends of the linear tread strip were joined together on the retread tire. These prior art tires are acceptable for multiple axle truck usage, but are generally not accepted for passenger cars, primarily because of their appearance and balance.
It has recently been disclosed that rebuilt tires can be produced by assembly of a seamless, preformed and cured annular tire tread onto a tire carcass. U.S. Pat. No. 3,815,651 discloses an endless precured tire tread of the type contemplated. The tread is generally moved into position on the tire carcass and bonded thereon. This construction results in a strong rebuilt tire having no transverse seam across the tread, thereby eliminating the appearance and balance problems found in most precured tread rebuilt tire structures.